1. Field of the Invention
This invention concerns a curl type tilt hinge for office automation equipment, which is mounted between a keyboard unit and a display unit of an office automation equipment, in particular, a compact personal computer, etc. and is favorable for opening and closing the keyboard unit, which is a first member, and the display unit, which is a second member, in a relative manner and stopping and maintaining these members at an arbitrary opening angle.
2. Description of the Prior Art
As a prior art, a tilt hinge for office automation equipment is known with which a fastening curl part, having a fastening curl member, is formed on a bearing plate part of a mounted member to be mounted to the main device unit, which is a first member, such as a keyboard unit, and upon inserting a rotating shaft, which supports a display unit, which is a second member and serves as an opening and closing member, into the fastening curl part, the fastening curl member is moved towards the bearing plate side by means of a fastening screw to fasten the outer circumference of the rotating shaft and generate frictional torque.
Japanese Un-examined Patent Publication No. Hei-10-47337 also discloses such a curl type tilt hinge, which is comprised of a mounting member, having a curl part provided with elasticity, a shaft that is press fitted into the abovementioned curl part of the mounting member, and a bracket that is mounted to this shaft, and with which the cross-sectional shape of inner side of the curl part is made a circular shape that is matched as much as possible to the outer shape of the shaft.
With the former of the above-described prior-art tilt hinges, though the frictional torque that the fastening curl part creates by fastening the outer circumference of the rotating shaft can be adjusted in each product by means of the fastening screw, the frictional torque, though changing slightly with time, is substantially fixed and the frictional torque cannot be made to vary in the process of opening and closing the display unit.
The latter of the above-described prior art (Japanese Un-examined Patent Publication No. Hei-10-47337), is called a stage-less tilt hinge since the keyboard unit and the display unit, which are the first member and second member, respectively, that are opened and closed in a relative manner, can be stopped and maintained at an arbitrary opening position in a stage-less manner. However, as shown in FIGS. 12 and 13, since the shape of the hole part 20a of curl part 20 will not be completely the same in each part but will vary no matter how high the precision is made, the points (indicated by filled circles) at which the outer circumference of a shaft 21, which is press fitted into curl part 20, contacts the inner side of the hole part 20a of curl part 20 will differ with each part and since the spring characteristics of the curl part will thus vary, the rotational torque created by each tilt hinge will not be the same.
Also, since the gap between the inner side of curl part 20 and the outer circumference of shaft 21, which is press fitted into this curl part 20, will obviously be extremely minute, lubrication effects will not be exhibited effectively. Though a collar, having a plurality of small holes, grooves, or indented parts, is thus press fitted between shaft 21 and the inner side of curl part 20, the number of parts is made large and this has been an obstacle in lowering the manufacturing cost.
3. Object(s) of the Invention
An object of this invention is to provide a tilt hinge for office automation equipment, with which, by means of a simple arrangement, the frictional torque can be made to vary in the process of the opening and closing operation of a keyboard unit, which is a first member that serves as the main device unit, and a display unit, which is a second member.
Another object of this invention is to provide a tilt hinge, with which the dispersion of the rotational torque that is generated is made as small as possible and yet with which component parts are eliminated to make the manufacturing cost low.
In order to achieve the above objects, this invention provides a tilt hinge for office automation equipment, comprised of a mounting member, having a mounting plate part and a bearing plate part that is bent at a right angle with respect to the mounting plate part, an engaging curl part, which is provided with elasticity and is disposed at the tip of the abovementioned bearing plate part of the mounting member, and a shaft, having a torque generating part that is press fitted into the engaging curl part, a tilt hinge for office automation equipment characterized in that the abovementioned engaging curl part is comprised of a fastening curl part, having a fastening curl member, and a modified engaging curl part, having the axial center in common with the fastening curl part, the torque generating part of the abovementioned shaft is comprised of a main torque generating part, which is press fitted into the abovementioned fastening curl part, and a sub torque generating part, which is press fitted into the abovementioned modified engaging curl part, and the relative rotational torque between the abovementioned shaft and engaging curl part is adjusted by moving the fastening curl member of the abovementioned fastening curl part in the circumferential direction by means of an adjustment screw and thereby adjusting the fastening force applied to the main torque generating part.
With this arrangement by this invention, oil grooves or oil holes for lubricating oil may be provided on the outer circumference of the main torque generating part of the abovementioned shaft that is fastened by the abovementioned fastening curl part.
Furthermore with this invention, the bearing hole of the abovementioned engaging curl part may be made to have a D-like cross-sectional shape and the outer shape of the sub torque generating part of the rotating shaft that is press fitted into the bearing hole may likewise be made to have a D-like cross-sectional shape.
Also with this invention, an expanding slot may be provided between the fastening curl part and modified engaging curl part of the abovementioned mounting member and a flange part, provided on the abovementioned shaft, may be engaged with this expanding slot.
Also with this invention, a flat part, which is press contacted against a portion of the abovementioned shaft in the axial direction, may be provided on at least a part of the inner side of the abovementioned engaging curl part.
With the above arrangement by this invention, the abovementioned engaging curl part may be comprised of independent members and be fixed to a separately provided mounting member.
Furthermore with this invention, the abovementioned engaging curl part may be comprised of at least two engaging curl parts that are made opposite in the direction of engagement.
Furthermore with this invention, the abovementioned shaft may be a rotating shaft.
Furthermore with this invention, the abovementioned shaft may be fixed and the abovementioned mounting member may be arranged to rotate about the axis of this shaft.
Furthermore with this invention, one or more oil grooves or indented parts for keeping lubricating oil may be provided on the outer circumference of the abovementioned shaft.
Also with this invention, the engaging curl part may be comprised of both a fastening curl part, which has a fastening curl member, and a modified engaging curl part.